Solid-Rocket Motor - Concerns About O-Rings. Pg 2

Further investigating their concerns about the Solid-Rocket-Motor joints and the potential failure of O-rings, NASA officials met with outside experts and representatives from the company supplying the O-rings. 

Following a review of the evidence, "their [the supplier's] first thought was that the O-ring was being asked to perform beyond its intended design and that a different type of seal should be considered."

This is the second page of the memo which documents the visits.  Click on the image for a clearer view.

Credits

NASA memo online, courtesy NASA.